This invention relates generally to the identification of paper money and other similar documents and more particularly to such identification for purposes of detection and apprehension of criminals.
Various prior art techniques have been used to identify paper money and other documents illegally obtained. Most of these prior art techniques have used methods which try to directly identify the person having custody of the illegally obtained documents in such a manner that apprehension is facilitated. Typically, such prior art methods use a dye and/or tear gas bomb which is set to explode after the criminal leaves the bank or other institution at which the robbery takes place.
The basic problem encountered with these explosive methods is that the criminal may become aware of such identification prior to detection by law enforcement authorities. Because of this, the criminal thus has an opportunity to overcome such identification prior to apprehension by the law enforcement authorities. Also, these exploding techniques frequently endanger innocent persons in the vicinity of the criminal when the identification takes place.
Another prior art method uses an odor producing material which is released onto the illegally obtained documents during or after the robbery as the documents are handled. This material produces a detectable odor after the scene of the crime to assist in locating the documents; however, the detectable odor diminishes over time so as to eventually lose its effectiveness.
Also, these prior art techniques in and of themselves generally are not able to identify the source of the money or paper and thus must be related to their source using other means. Because the identification of the stolen goods is readily apparent to the criminal, the criminal generally is able to dispose of the identified goods so that detection of the goods through subsequent use by the criminal is not practically available.
Another prior art technique uses a normally invisible powder to coat the money or other paper but which can be made visible when exposed to ultra violet light. This powder rubs off on persons handling same so as to permit identification of the person possibly by exposure to ultra violet light. Because this powder is normally invisible, subsequent use of the thusly identified money is encouraged. Thus, detection through subsequent use is possible. One of the major problems associated with this prior art technique is that, because the powder is normally invisible, it is difficult to identify the money during subsequent use as having the powder thereon since it is not practical for all money to be exposed to ultra violet light. Thus, detection during subsequent use is generally not made. Also, this prior art technique generally is not able to identify the source of the money, even when detection is made, thereby making it especially difficult to obtain conviction of the criminal for the original criminal action.